In the publication described in Patent Document 1, there is disclosed a tire testing device which includes a lower frame, a portal frame, a lower chuck, and an upper chuck. The portal frame is uprightly provided in the lower frame. The portal frame includes a pair of vertical frames which respectively extends upward in the vertical direction from both ends of the lower frame in the longitudinal direction and a horizontal frame which extends between the upper ends of the vertical frames. The lower chuck is attached to the lower frame. The upper chuck is attached to the horizontal frame of the portal frame. Each of the lower chuck and the upper chuck includes a rotation member. In the tire testing device, air is supplied to an inner space of a tire while the tire is nipped between the lower chuck and the upper chuck. Further, various performance tests are performed while the respective rotation members rotate the tire.
In a state where air is supplied to the inner space of the tire, the pneumatic pressure of the inner space applies a force (hereinafter, referred to as a separating force) for separating the upper chuck from the lower chuck to the upper chuck. The separating force is transmitted from the upper chuck to the vertical frame and the lower frame through the horizontal frame.